Qhov sib txawv tseem ceeb ntawm RNA polymerase core thiab holoenzyme yog RNA polymerase core yog ib qho enzyme uas tsis muaj sigma yam, thaum RNA polymerase holoenzyme yog ib qho enzyme uas muaj cov yam ntxwv ntawm sigma.
Kev hloov pauv hauv cov kab mob yog txheej txheem uas ib ntu ntawm cov kab mob DNA tau theej rau hauv mRNA strand tshiab nrog kev siv RNA polymerase enzyme. Cov txheej txheem no tshwm sim nyob rau hauv peb kauj ruam tseem ceeb: pib, elongation, thiab txiav. Cov kab mob RNA polymerase yog tsim los ntawm 6 subunits. RNA polymerase core muaj β, β', α2 thiab ω subunits. Qhov no RNA polymerase core hloov mus rau hauv holoenzyme thaum σ (sigma) yam tseem ceeb yog khi rau cov enzyme core. RNA polymerase core thiab holoenzyme yog ob hom kab mob RNA polymerase enzyme.
RNA Polymerase Core yog dab tsi?
RNA polymerase core yog ib qho enzyme koom nrog hauv cov kab mob sib kis uas tsis pub dawb los ntawm sigma yam. Nws muaj 5 subunits uas yog β, β', α2, thiab ω. Cov enzyme no tsis pib qhov kev hloov pauv tshwj xeeb los ntawm cov kab mob thiab phage DNA txhawb nqa. Qhov no yog vim nws tsis paub txog cov kab mob tshwj xeeb lossis phage DNA txhawb nqa. Txawm li cas los xij, qhov enzyme no khaws lub peev xwm los sau RNA los ntawm cov txheej txheem pib tsis tshwj xeeb. Ntxiv mus, qhov sib ntxiv ntawm sigma yam rau qhov enzyme no tso cai rau cov enzyme pib RNA synthesis los ntawm cov kab mob tshwj xeeb thiab phage txhawb nqa. Qhov hnyav molecular ntawm RNA polymerase core enzyme yog kwv yees li 400 kDa.
Daim duab 01: RNA Polymerase Core
Cov enzyme tseem ceeb muaj cov khoom catalytic ntawm RNA polymerase. Lub α subunit yog homodimer uas yog 36.5 kDa loj. Nws yog encoded los ntawm rpoA gene. Lub luag haujlwm ntawm lub subunit no yog RNAP sib dhos, kev cuam tshuam nrog DNA, thiab cov ntsiab lus hloov pauv rau kev tswj hwm kev hloov pauv. Β subunit yog 150.4 kDa loj. Nws yog encoded los ntawm rpoB noob. Cov haujlwm ntawm lub subunit no yog DNA thiab RNA khi, RNA synthesis, NTP khi, RMP khi qhov chaw, thiab σ factor binding. β′ subunit yog 155 kDa loj, thiab nws yog encoded los ntawm rpoC noob. Lub luag haujlwm ntawm lub subunit no yog DNA khi, RNA synthesis, catalytic Mg 2+ kev sib koom tes, ppGpp binding site 1, thiab σ factor binding. Tsis tas li ntawd, qhov tseem ceeb ω yog 10.2 kDa loj thiab encoded los ntawm rpoZ noob. Kev ua haujlwm ntawm ω yam yog RNAP folding thiab ppGpp khi qhov chaw 1.
RNA Polymerase Holoenzyme yog dab tsi?
RNA polymerase holoenzyme yog tsim los ntawm cov khoom tshwj xeeb hu ua sigma yam tsis yog β, β', α2, thiab ω subunits. Vim yog qhov tseem ceeb ntawm sigma, RNA polymerase holoenzyme tuaj yeem paub txog cov neeg txhawb nqa. Qhov zoo tshaj plaws sigma kuj pab tau qhov tseeb qhov chaw ntawm RNA polymerase holoenzyme thiab unwinding ntawm qhov chaw pib. Thaum lub sij hawm sigma ua nws qhov kev xav tau thiab kev ua haujlwm tshwj xeeb, nws cuam tshuam los ntawm RNA polymerase holoenzyme thaum lub catalytic feem (β, β', α2, thiab ω) ntawm RNA polymerase tseem nyob hauv DNA thiab txuas ntxiv mus.
Daim duab 02: RNA Polymerase Holoenzyme
Tus naj npawb ntawm sigma yam txawv ntawm cov kab mob. E. coli muaj xya qhov laj thawj. Ntxiv mus, cov yam ntxwv sigma yog qhov txawv ntawm lawv qhov hnyav molecular. Piv txwv li, σ70 yog qhov ua sigma nrog qhov hnyav molecular ntawm 70 kDa. Sib txawv sigma yam yog siv los ntawm cov kab mob nyob rau hauv ib puag ncig sib txawv. Piv txwv ntawm qhov sib txawv σ muaj xws li; σ19, σ24, σ18, σ32, σ38, thiab σ54
Dab tsi yog qhov zoo sib xws ntawm RNA Polymerase Core thiab Holoenzyme?
- RNA polymerase core thiab holoenzyme yog ob hom kab mob RNA polymerase enzyme.
- Ob daim ntawv muaj feem cuam tshuam nrog cov kab mob transcription.
- Lawv muaj subunits.
- Lawv yog cov protein molecules ua los ntawm cov amino acids.
Qhov txawv ntawm RNA Polymerase Core thiab Holoenzyme yog dab tsi?
RNA polymerase core yog ib qho enzyme uas tsis muaj qhov ua sigma, thaum RNA polymerase holoenzyme yog ib qho enzyme uas muaj qhov ua sigma. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm RNA polymerase core thiab holoenzyme. Tsis tas li ntawd, RNA polymerase core feem ntau koom nrog hauv cov kauj ruam elongation ntawm cov ntawv sau, thaum RNA polymerase holoenzyme feem ntau catalyzes hauv cov kauj ruam pib ntawm kev sau ntawv.
Cov hauv qab no qhia txog qhov sib txawv ntawm RNA polymerase core thiab holoenzyme hauv daim ntawv tabular rau ib sab ntawm kev sib piv.
Summary – RNA Polymerase Core vs Holoenzyme
Bacterial RNA polymerase yog ntau subunit DNA-dependent enzyme. Nws koom nrog hauv kev sau cov kab mob. Nws yog qhov tseem ceeb enzyme ntawm cov noob qhia thiab lub hom phiaj ntawm kev tswj hwm. RNA polymerase core thiab holoenzyme yog ob hom kab mob RNA polymerase enzyme. RNA polymerase core tsis muaj qhov ua sigma, thaum RNA polymerase holoenzyme muaj cov yam ntxwv sigma. Yog li, qhov no qhia txog qhov sib txawv ntawm RNA polymerase core thiab holoenzyme.
